The present invention relates to a device for dispensing granular or powdered material in measured quantities, such as coffee, laundry detergent, and the like.
Various devices are known in the art for dispensing measured quantities of granular or powdered material. For example, U.S. Pat. No. 4,079,860 discloses such a device incorporating a hopper disposed over a rotatable cylindrical valve member which defines a variable volume chamber. Another example includes U.S. Pat. No. 4,162,751 which discloses a measuring and dispensing apparatus adapted to be secured to a jar containing powdered or granular material. The device contains a rotor which includes an adjustable measuring compartment to receive the granular material from the jar. The rotor can be moved by way of a selector device from a filling position to a dispensing position. U.S. Pat. No. 774,326, U.S. Pat. No. 2,820,577, and U.S. Pat. No. 1,431,582 also disclose various other devices for dispensing a measured quantity of material.
The conventional devices, such as those described in the above mentioned patents, have proven to be inadequate for various reasons. For example, the rotating action of the rotor described in the '751 patent tends to continually compact the granular material between the cylinder edge and the discharge opening of the hopper. Also, the granular material eventually finds its way between the working surfaces of the rotor and body or hopper causing the mechanism to jam. The arrangement of the piston element defining the adjustable measuring compartment is such that the piston is moved always in opposition to the granular material, which will eventually cause the piston to jam.
Devices such as that disclosed in the '860 patent provide relatively complicated and inaccessible devices for changing the volume of the dispensing chamber. This device also has the distinct disadvantage that the material contained in the hopper portion would tend to become compacted.
The present invention provides an improved granular material dispensing apparatus which eliminates the disadvantages of the prior art devices.